diff --git a/README.md b/README.md
index 570f455..2f44a56 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@
 </p>
 
 <p align="center">
-  <a href="https://stackmap-site.vercel.app">Website</a> · <a href="https://stackmap-site.vercel.app/docs">Docs</a> · <a href="https://stackmap-site.vercel.app/examples">Examples</a>
+  <a href="https://stackmap.omsimos.com">Website</a> · <a href="https://stackmap.omsimos.com/docs">Docs</a> · <a href="https://stackmap.omsimos.com/examples">Examples</a>
 </p>
 
 Ask your coding agent to diagram a codebase, a system, a process or a request. It writes a small typed JSON, stackmap validates it with repair hints the agent acts on, lays it out, and delivers one self-contained HTML viewer. No server, no account, nothing to install to open it.
@@ -89,7 +89,7 @@ The agent writes `.stackmap/<name>/diagram.json`, validates and repairs it, and
 - **Edges** can be `async` or a `return`, with a `tone` for the main path, security crossings and failure paths.
 - **No coordinates:** stackmap lays everything out, with [ELK](https://eclipse.dev/elk/) for architecture and dataflow and its own layout for lanes and sequences.
 
-Full reference: [skill/references/schema.md](skill/references/schema.md), or the [schema reference](https://stackmap-site.vercel.app/docs/schema) on the website. Modelling guidance: [authoring contract](skill/references/authoring-contract.md).
+Full reference: [skill/references/schema.md](skill/references/schema.md), or the [schema reference](https://stackmap.omsimos.com/docs/schema) on the website. Modelling guidance: [authoring contract](skill/references/authoring-contract.md).
 
 ## The CLI
 
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 91fce8a..d41ff12 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -13,7 +13,7 @@
     "html",
     "dataflow"
   ],
-  "homepage": "https://github.com/hyamero/stackmap#readme",
+  "homepage": "https://stackmap.omsimos.com",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/hyamero/stackmap.git",
diff --git a/site/lib/seo.test.ts b/site/lib/seo.test.ts
index c1c7213..2a4d23e 100644
--- a/site/lib/seo.test.ts
+++ b/site/lib/seo.test.ts
@@ -20,20 +20,16 @@ function pageRoutes(dir = join(site, 'app')): string[] {
 }
 
 describe('siteUrl', () => {
-  it('uses the production domain Vercel reports', () => {
-    expect(siteUrl({ VERCEL_PROJECT_PRODUCTION_URL: 'stackmap.dev' }).href).toBe('https://stackmap.dev/');
-  });
-
-  it('falls back to the project domain outside Vercel', () => {
-    expect(siteUrl({}).href).toBe('https://stackmap-site-hyameros-projects.vercel.app/');
+  it('is the custom domain, never a vercel.app one', () => {
+    expect(siteUrl().href).toBe('https://stackmap.omsimos.com/');
   });
 });
 
 describe('robots', () => {
   it('lets crawlers in on production and points them at the sitemap', () => {
-    const r = robotsFor({ VERCEL_ENV: 'production', VERCEL_PROJECT_PRODUCTION_URL: 'stackmap.dev' });
+    const r = robotsFor({ VERCEL_ENV: 'production', VERCEL_PROJECT_PRODUCTION_URL: 'stackmap-site.vercel.app' });
     expect(r.rules).toEqual({ userAgent: '*', allow: '/' });
-    expect(r.sitemap).toBe('https://stackmap.dev/sitemap.xml');
+    expect(r.sitemap).toBe('https://stackmap.omsimos.com/sitemap.xml');
   });
 
   it('keeps previews and local builds out of the index', () => {
diff --git a/site/lib/seo.ts b/site/lib/seo.ts
index cc7f7c5..602f662 100644
--- a/site/lib/seo.ts
+++ b/site/lib/seo.ts
@@ -21,15 +21,14 @@ export const OPEN_GRAPH = {
 /** Every static page; the sitemap test fails when a page.tsx is added without its route here. */
 export const ROUTES = ['/', '/docs', '/docs/viewer', '/docs/cli', '/docs/schema', '/docs/brands', '/examples'] as const;
 
-// Vercel sets the production domain on every deployment, previews included, so canonical and OG URLs
-// never point at a preview. It follows a custom domain once one is attached.
-export function siteUrl(env: Env = process.env): URL {
-  return new URL(`https://${env.VERCEL_PROJECT_PRODUCTION_URL ?? 'stackmap-site-hyameros-projects.vercel.app'}`);
-}
+// Pinned rather than read from VERCEL_PROJECT_PRODUCTION_URL: Vercel reports the project's vercel.app domain there
+// even with the custom domain attached, and canonical, OG and sitemap URLs must all name the one real address.
+export const SITE_URL = 'https://stackmap.omsimos.com';
+export const siteUrl = (): URL => new URL(SITE_URL);
 
 export function robotsFor(env: Env = process.env): MetadataRoute.Robots {
   if (env.VERCEL_ENV !== 'production') return { rules: { userAgent: '*', disallow: '/' } };
-  return { rules: { userAgent: '*', allow: '/' }, sitemap: new URL('/sitemap.xml', siteUrl(env)).href };
+  return { rules: { userAgent: '*', allow: '/' }, sitemap: new URL('/sitemap.xml', siteUrl()).href };
 }
 
 export function sitemapFor(base: URL = siteUrl()): MetadataRoute.Sitemap {